The invention is designed to increase the safety and ease of a swimmer in exiting the water to board a boat. The invention includes a platform which is preferably positioned below the level of the water where it functions as a zone of transition to allow a swimmer or diver the ability to move easily from a horizontal swimming body position to a vertical boarding body position. The platform may also provide swimmers and divers with an area to rest and recover their strength and adjust or remove equipment.
In the past, getting on board a boat from the water, in some cases with heavy SCUBA equipment, was clumsy, fatiguing, dangerous, and at times impossible to do without assistance. Heretofore, there have been four basic methods of boarding a boat from the water, namely, (1) without aid; (2) with the aid of a swim step; (3) with the aid of a vertical ladder; and (4) with the aid of an inclined ramp.
The use of muscle power alone to get over the side of a boat is by far the most difficult and dangerous of the abovementioned methods. This method requires a great deal of upper body strength and may not be possible with SCUBA equipment, or when boarding a boat with over 12 inches of freeboard. A fatigued swimmer has no means of resting and regaining his or her strength prior to boarding. The time required by this method of exiting the water may leave swimmers vulnerable to attack by sharks or other marine predators.
Swim steps are usually mounted one foot or more above the water line, and usually extend a maximum of 24 inches beyond the transom. They require balance and upper body strength similar to that required by unaided boarding, and share all of the disadvantages of unaided boarding. An example of such swimming aid structures are described in U.S. Pat. Nos. 3,587,123 and 4,495,883.
Boarding with the use of a ladder offers some improvement over unaided boarding. Ladders may also be used in conjunction with a swim step as shown in U.S. Pat. No. 4,765,438. On the negative side, ladders still require balance and upper body strength. The difficulties are compounded by the inward curve of most boat hulls. The ladder provides a very poor resting area for fatigued swimmers. When a swimmer approaches a ladder, he must take hold of the ladder and move into a vertical body position. He must then remove his swim fins so that he can use the steps of the ladder. This position removes his ability to propel himself or to resist water current. The vertical body position also creates a pressure differential of approximately 1/2 PSI between the level of the lungs and the surface air pressure. This pressure differential can add significantly to a swimmer or diver's fatigue and anxiety.
Inclined diving ramps are used on commercial SCUBA diving boats. These platforms are usually attached to the transom of the boat at a point one foot or more above the water line. The opposite end of the platform can be lowered to a point one foot or more below the surface of the water and held in place by transom mounted cables. This method of boarding is easy, rapid, safe, and requires very little upper body strength. On the negative side, the inclined ramps are expensive, ungainly, and difficult to mount and maintain. Ramps are unsuited to boats with narrow transoms such as sail boats, small boats, inflatable boats and boats with protrusions such as rudders or stern drives. Few boat owners would wish to permanently spoil the aesthetics of their craft with such ungainly structures.
Examples of such prior art ramps are found in U.S. Pat. No. 4,538,314 showing an inclined ramp with an abbreviated platform utilizing a rigid lever structure, and U.S. Pat. No. 4,723,929 which shows an inflatable ramp that is not capable of submerged deployment. Still another boarding ramp is shown in U.S. Pat. No. 2,914,779 where the swimmer support never goes below the surface of the water. A submersible platform is taught in U.S. Pat. No. 4,773,887. This complicated structure takes the form of an elevator. It is totally supported by the boat, and would require a boat of substantial displacement to support its bulk. A submerged ramp is shown in U.S. Pat. No. 3,891,053, which suffers from similar handicaps to the former device. In general, none of these devices provide an adequate stable area for a swimmer to rest or to remove or adjust bulky equipment. In fact, none of the above referenced prior art patents describe or offer the simple, stable, and advantageous structure of the present invention.
In contradistinction to the prior art, the present invention is an highly functional solution to the problems raised with the traditional boarding methods. The invention is designed to increase the safety and ease of exiting the water to board a boat while providing a safe and convenient resting area. It is capable of attaching to and functioning with the ladder systems. It may also completely replace the ladder on boats with low freeboard such as inflatable boats.
It should thus be clear that the prior art in the subject area of interest generally lacks the utility, helpfulness, simplicity, ruggedness, and safety that is most required in a flotation supported submersible swim platform, and such a platform which obviates the aforementioned shortcomings of the prior art would constitute a significant advancement in the art.